Gas supply system and gas supply method

ABSTRACT

A gas supply system includes a first flow channel connected to a first gas source of a first gas, formed inside a ceiling or a sidewall of the treatment container, and communicating with the treatment space through a plurality of first gas discharge holes, a second flow channel connected to a second gas source of a second gas, formed inside the ceiling or the sidewall of the treatment container, and communicating with the treatment space through a plurality of second gas discharge holes, and a plurality of first diaphragm valves, wherein each of the first diaphragm valves is provided between the first flow channel and the first gas discharge hole to correspond to the first gas discharge hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/180,047 filed Nov. 5, 2018, which is based on and claims the benefitof priority from Japanese Patent Application No. 2017-215589 filed onNov. 8, 2017, and the entire contents of which are incorporated hereinby reference.

TECHNICAL FIELD

Exemplary embodiments of the present disclosure relates to a gas supplysystem and a gas supply method.

BACKGROUND

Japanese Patent No. 3856730 discloses a gas supply system that suppliesgases from a plurality of gas sources to a treatment container. Thesystem disclosed in Japanese Patent No. 3856730 generates a mixed gasfrom the plurality of gas sources, then branches the generated mixed gasand supplies the branched gas to the treatment container.

SUMMARY

In an aspect, there is provided a gas supply system that supplies a gasto a treatment space within a treatment container of a substratetreatment apparatus. The system includes a first flow channel, aplurality of first gas discharge holes, a second flow channel, a secondgas discharge hole, and a plurality of first diaphragm valves. The firstflow channel, formed inside a ceiling or a sidewall of the treatmentcontainer, connects to a first gas source of a first gas andcommunicates with the treatment space through the plurality of first gasdischarge holes. The second flow channel, formed inside the ceiling orthe sidewall of the treatment container, connects to a second gas sourceof a second gas and communicates with the treatment space through thesecond gas discharge hole. Each of the first diaphragm valves isprovided between the first flow channel and the first gas discharge holeto correspond to the first gas discharge hole.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, exemplaryembodiments, and features described above, further aspects, exemplaryembodiments, and features will become apparent by reference to thedrawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a gas supply system according to afirst exemplary embodiment.

FIG. 2 is a cross-sectional view schematically illustrating a firstdiaphragm valve.

FIG. 3 is a diagram schematically illustrating a lower structure of thefirst diaphragm valve.

FIG. 4 is a cross-sectional view schematically illustrating a substratetreatment system according to the first exemplary embodiment.

FIG. 5 is a schematic cross-sectional view of an upper electrode in FIG.4 .

FIG. 6 is a schematic diagram when a first flow channel is seen in aplan view.

FIG. 7 is a graph illustrating a relationship between a control pressureand the position of an orifice in the first flow channel.

FIG. 8 is a flow diagram of a gas supply method according to the firstexemplary embodiment.

FIG. 9 is a schematic diagram of a gas supply system according to asecond exemplary embodiment.

FIG. 10 is a schematic cross-sectional view of an upper electrode of thegas supply system according to the second exemplary embodiment.

FIG. 11 is a schematic diagram when the first flow channel and a secondflow channel are seen in a plan view.

FIG. 12 is a graph illustrating a relationship between a pressure and aflow rate for each discharge hole.

FIG. 13 is a graph illustrating a relationship between the degree ofpiezoelectric opening and a flow rate for each discharge hole.

FIG. 14 is a flow diagram a gas supply method according to the secondexemplary embodiment.

FIGS. 15A and 15B are an example of a relationship between the amount ofpiezoelectric displacement of a piezoelectric element and an appliedvoltage.

FIGS. 16A and 16B are graphs obtained by comparing a relationshipbetween a flow rate and an applied voltage with a relationship between aflow rate and the amount of piezoelectric displacement.

FIG. 17 is an example of a configuration in which a flow rateself-diagnosis is performed.

FIGS. 18A and 18B are graphs illustrating a relationship between a flowrate and a time in a comparative example and an example.

FIGS. 19A and 19B are graphs illustrating a relationship between a flowrate and a time in the comparative example and the example.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The exemplaryembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other exemplary embodiments may beutilized, and other changes may be made, without departing from thespirit or scope of the subject matter presented here.

A reduction in the size of a semiconductor device needs repeatinglamination and removal in an atomic level. Such process may need toimprove the response speed and switching speed of a process gas. Thesystem disclosed in Japanese Patent No. 3856730 has room for improvingthe response speed and the switching speed of the process gas.

In a first aspect, there is provided a gas supply system that supplies agas to a treatment space within a treatment container of a substratetreatment apparatus. The system includes a first flow channel, aplurality of first gas discharge holes, a second flow channel, a secondgas discharge hole, and a plurality of first diaphragm valves. The firstflow channel, formed inside a ceiling or a sidewall of the treatmentcontainer, connects to a first gas source of a first gas andcommunicates with the treatment space through the plurality of first gasdischarge holes. The second flow channel, formed inside the ceiling orthe sidewall of the treatment container, connects to a second gas sourceof a second gas and communicates with the treatment space through thesecond gas discharge hole. Each of the first diaphragm valves isprovided between the first flow channel and the first gas discharge holeto correspond to the first gas discharge hole.

In this system, the first gas is supplied from the first flow channelthrough the plurality of first gas discharge holes to the treatmentspace, and the second gas is supplied from the second flow channelthrough the plurality of second gas discharge holes to the treatmentspace. In this manner, the first gas and the second gas are supplied tothe treatment space without being merged with each other. Therefore, thegas supply system can save a time which will be taken until the mergedgas reaches the treatment container, as compared with a case where thefirst gas and the second gas are merged with each other before thesegases are supplied to the treatment container. This leads to anexcellent response speed. In addition, each of the first diaphragmvalves is disposed between the first flow channel and the first gasdischarge hole, that is, in the vicinity of the treatment space.Therefore, the gas supply system can supply and control the first gaswith good responsiveness through the first diaphragm valves, and canperform high-speed switching between a case where only the second gas issupplied to the treatment space and a case where a mixed gas of thefirst gas and the second gas is supplied to the treatment space. Thus,the gas supply system 1 can improve the response speed of a process gas,and also further improve the switching speed of the process gas.Further, the gas supply system can control the supply and stop of thefirst gas for each first gas discharge hole.

In an exemplary embodiment, the first flow channel may have a supplyport to which the first gas is supplied and an exhaust port from whichthe first gas is exhausted, and extends from the supply port to theexhaust port. The gas supply system may further include: a controlvalve, provided upstream of the supply port, which controls the firstgas supplied to the supply port at a predetermined pressure; a pluralityof first orifices which are each provided between the first flow channeland the first gas discharge hole to correspond to the first gasdischarge hole; and a first controller that brings the control valve andthe plurality of first diaphragm valves into operation, and each firstdiaphragm valve may control a supply timing of the first gas suppliedfrom an outlet of the first orifice to the first gas discharge hole.

In this case, the first gas is supplied to the first flow channel at apredetermined pressure by the control valve, and circulates from thesupply port of the first flow channel to the exhaust port. The first gasis supplied from the outlets of the first orifices to the first gasdischarge hole by switching of the first diaphragm valves. Therefore,the gas supply system can stabilize the pressure of the first flowchannel in the entire flow channel, and branch the first gas from eachof a plurality of points of the first flow channel of which the pressureis stabilized. Thus, the gas supply system can reduce a pressure errorfor each first gas discharge hole. In addition, the gas supply systemincludes the first orifices corresponding to the first gas dischargehole, and thus it is possible to suppress a fluctuation in pressurewithin the first flow channel due to switching of the first diaphragmvalves.

In an exemplary embodiment, the gas supply system may further include afirst pressure detector that detects a pressure of the first gas in aflow channel between the control valve and the supply port, and thecontrol valve may control the pressure of the first gas on the basis ofa detection result of the first pressure detector. In this case, the gassupply system can control the pressure of the first gas supplied to thefirst flow channel on the basis of the downstream pressure of thecontrol valve.

In an exemplary embodiment, the gas supply system may further include asecond pressure detector that detects the pressure of the first gasexhausted from the exhaust port, and the first controller may calculatethe pressure of the first gas at an arrangement position of each firstorifice on the basis of a detection result of the first pressuredetector and a detection result of the second pressure detector, andcontrol a supply timing of the first gas through each first diaphragmvalve on the basis of a result of calculation of the pressure. In thiscase, the gas supply system can predict the pressure of the first gas atthe arrangement position of each of the first orifices, and thus it ispossible to improve the accuracy of the flow rate of the first gassupplied from each first gas discharge hole.

In an exemplary embodiment, the gas supply system may further include anexhaust orifice provided in the exhaust port of the first flow channel.In this case, the gas supply system can suppress the differentialpressure of the first gas dependent on a position within the first flowchannel.

In an exemplary embodiment, the gas supply system may further include atemperature detector that detects a temperature of the first gas in thefirst flow channel, and the control valve may control a flow rate of thefirst gas on the basis of a detection result of the temperaturedetector. In this case, the gas supply system can adjust a flow rate inconsideration of a change in the flow rate of the first gas with achange in temperature.

In an exemplary embodiment, each of the first diaphragm valves mayinclude a piezoelectric element that drives a diaphragm, the gas supplysystem may further include a detector that measures an amount ofdisplacement of the piezoelectric element, and the first controller maycontrol a degree of opening of the first diaphragm valve using theamount of displacement as a parameter. In this case, the gas supplysystem can suppress a control error of the degree of opening of thefirst diaphragm valve, as compared with a case where a control voltageis used as a parameter.

In an exemplary embodiment, the gas supply system may further include aplurality of second diaphragm valves which are each provided between thesecond flow channel and the second gas discharge hole to correspond tothe second gas discharge hole. In this case, the amount of supply of thesecond gas in each second gas discharge hole is controlled by the seconddiaphragm valve. Thus, the gas supply system can control supply from thefirst flow channel and supply from the second flow channel independentlyof each other.

In an exemplary embodiment, the gas supply system may further include: afirst gas box that has a plurality of gas sources including the firstgas source, and supplies a first mixed gas, obtained from the pluralityof gas sources, to the first flow channel; a first flow rate controllerprovided between the first gas box and the first flow channel; a secondgas box that has a plurality of gas sources including the second gassource, and supplies a second mixed gas, obtained from the plurality ofgas sources, to the second flow channel; a second flow rate controllerprovided between the second gas box and the second flow channel; and asecond controller that brings the plurality of first diaphragm valvesand the plurality of second diaphragm valves into operation. The firstflow channel may be a closed space to which the first mixed gas issupplied, the second flow channel may be a closed space to which thesecond mixed gas is supplied, and the second controller may bring eachof the first diaphragms into operation so that a flow rate of the firstmixed gas within the first flow channel is distributed and controlledfor each of the first gas discharge holes, and bring each of the seconddiaphragms into operation so that a flow rate of the second mixed gaswithin the second flow channel is distributed and controlled for each ofthe second gas discharge holes.

In this case, the first mixed gas including the first gas is controlledby the first flow rate controller to a predetermined flow rate, and issupplied to the first flow channel. Each of the first diaphragms isoperated by the second controller. Thereby, the first mixed gas having apredetermined flow rate within the first flow channel is distributed andcontrolled for each first gas discharge hole. The second mixed gasincluding the second gas is controlled by the second flow ratecontroller to a predetermined flow rate, and is supplied to the secondflow channel. Each of the second diaphragms is operated by the secondcontroller. Thereby, the second mixed gas within the second flow channelis distributed and controlled for each second gas discharge hole. Inthis manner, the gas supply system can distribute and control a flowrate for each discharge hole.

In an exemplary embodiment, the gas supply system may further include: athird pressure detector that measures a pressure of the first mixed gassupplied to the first flow channel; and a fourth pressure detector thatmeasures a pressure of the second mixed gas supplied to the second flowchannel, and the second controller may control degrees of opening of theplurality of first diaphragm valves on the basis of a relationshipbetween a flow rate, a pressure and a degree of valve opening acquiredin advance for each of the first gas discharge holes, a measurementresult of the third pressure detector, and a target flow rate which isset for each of the first gas discharge holes, and control degrees ofopening of the plurality of second diaphragm valves on the basis of arelationship between a flow rate, a pressure and a degree of valveopening acquired in advance for each of the second gas discharge holes,a measurement result of the fourth pressure detector, and a target flowrate which is set for each of the second gas discharge holes. In thiscase, the gas supply system can control the degrees of opening of thefirst diaphragm valve and the second diaphragm valve using arelationship acquired in advance.

In an exemplary embodiment, each of the first diaphragm valves and eachof the second diaphragm valves may include a piezoelectric element thatdrives a diaphragm, the gas supply system may further include a detectorthat measures an amount of displacement of the piezoelectric element,and the second controller may control a degree of opening of the firstdiaphragm valve and a degree of opening of the second diaphragm valveusing the amount of displacement as a parameter. In this case, the gassupply system can suppress control errors of the degrees of opening ofthe first diaphragm valve and the second diaphragm valve, as comparedwith a case where a control voltage is used as a parameter.

In a second aspect, there is provided a gas supply method in a gassupply system that supplies a gas to a treatment space within atreatment container of a substrate treatment apparatus. The gas supplysystem includes a first flow channel, a plurality of first gas dischargehole, a second flow channel, a second gas discharge hole, a plurality offirst orifices, a plurality of first diaphragm valves, and a controlvalve. The first flow channel, formed inside a ceiling or a sidewall ofthe treatment container, connects to a first gas source of a first gas.The first flow channel has a supply port to which the first gas issupplied and an exhaust port from which the first gas is exhausted,extends from the supply port to the exhaust port, and communicates withthe treatment space through the plurality of first gas discharge holes.The second flow channel, formed inside the ceiling or the sidewall ofthe treatment container, connects to a second gas source of a second gasand communicates with the treatment space through the second gasdischarge hole. The plurality of first orifices is provided between thefirst flow channel and the first gas discharge hole to correspond to thefirst gas discharge hole. Each of the first diaphragm valves is providedbetween the first flow channel and the first gas discharge hole tocorrespond to the first gas discharge hole, and controls a supply timingof the first gas supplied from an outlet of the first orifice to thetreatment space. The control valve is provided upstream of the supplyport, and controls a flow rate of the first gas from the supply port tothe exhaust port to a predetermined flow rate. The gas supply methodincludes: a step of setting each of the first diaphragm valves to beclosed and supplying the second gas from the second gas discharge holeto the treatment space, in a state where the first gas is circulated ata predetermined flow rate from the supply port of the first flow channelto the exhaust port; and a step of setting the at least one firstdiaphragm valve to be opened and supplying the second gas from thesecond gas discharge hole to the treatment space, in a state where thefirst gas is circulated at a predetermined flow rate from the supplyport of the first flow channel to the exhaust port.

According to this gas supply method, it is possible to continue tosupply the second gas, for example, as a main gas to the treatmentspace, and to intermittently supply the first gas, for example, as anadditive gas at high speed to the treatment space. Therefore, in the gassupply method, it is possible to improve the response speed of a processgas, and to further improve the switching speed of the process gas.

In a third aspect, there is provided a gas supply method in a gas supplysystem that supplies a gas to a treatment space within a treatmentcontainer of a substrate treatment apparatus. The gas supply systemincludes a first gas box, a first flow rate controller, a first flowchannel, a plurality of first gas discharge holes, a plurality of firstdiaphragm valves, a second gas box, a second flow rate controller, asecond flow channel, a plurality of second gas discharge holes, and aplurality of second diaphragm valves. The first gas box has a pluralityof gas sources, and supplies a first mixed gas obtained from theplurality of gas sources. The first flow rate controller is provided ona downstream side of the first gas box. The first flow channel is aclosed space, formed inside a ceiling or a sidewall of the treatmentcontainer, connects to the first flow rate controller, to which thefirst mixed gas is supplied, and communicates with the treatment spacethrough the plurality of first gas discharge holes. Each of the firstdiaphragm valves is provided between the first flow channel and thefirst gas discharge hole to correspond to the first gas discharge hole.The second gas box has a plurality of gas sources, and supplies a secondmixed gas obtained from the plurality of gas sources. The second flowrate controller is provided on a downstream side of the second gas box.The second flow channel is a closed space, formed inside the ceiling orthe sidewall of the treatment container, connects to the second flowrate controller, to which the second mixed gas is supplied, andcommunicates with the treatment space through the plurality of secondgas discharge holes. Each of the second diaphragm valves is providedbetween the second flow channel and the second gas discharge hole tocorrespond to the second gas discharge hole. The gas supply methodincludes: a step of setting the first diaphragm valve to be opened andsetting the second diaphragm valve to be closed; and a step of settingthe first diaphragm valve to be closed and setting the second diaphragmvalve to be opened.

According to this gas supply method, it is possible to improve theresponse speed of a process gas, and to further improve the switchingspeed of the process gas.

According to various aspects and exemplary embodiments of the presentdisclosure, it is possible to provide a gas supply system enhanced tocontrol a plurality of gases and execute a process.

Hereinafter, various exemplary embodiments will be described in detailwith reference to the accompanying drawings. In the respective drawings,the same or equivalent portions are denoted by the same referencenumerals and signs.

First Exemplary Embodiment

[Outline of Gas Supply System]

FIG. 1 is a schematic diagram of a gas supply system 1 according to afirst exemplary embodiment. FIG. 1 shows the gas supply system 1 thatsupplies gases to a treatment space within a chamber 12 (an example of atreatment container) of a substrate treatment apparatus. The gas supplysystem 1 includes a first gas source GS1 and a second gas source GS2.The first gas source GS1 stores a first gas. The second gas source GS2stores a second gas. The first gas and the second gas are arbitrary. Asan example, the second gas may be a main gas of a process, and the firstgas may be an additive gas of the process.

The gas supply system 1 includes a first main flow channel L10 and asecond main flow channel L20. The first main flow channel L10 connectsthe first gas source GS1 and a first flow channel L1 of a chamber 12through a supply port IN1. The second main flow channel L20 connects thesecond gas source GS2 of the second gas and a second flow channel L2 ofthe chamber 12 through a supply port IN4. The first main flow channelL10 and the second main flow channel L20 are formed by, for example,piping.

The first flow channel L1 is connected to the first gas source GS1, andis formed inside an upper electrode (an example of a ceiling) of thechamber 12 or inside a sidewall of the chamber 12. The first flowchannel L1 has the supply port IN1 to which the first gas is suppliedand an exhaust port OT1 from which the first gas is exhausted, andextends from the supply port IN1 to the exhaust port OT1. The exhaustport OT1 is connected to an exhaust apparatus 51 that exhausts thechamber 12 through an exhaust flow channel EL.

The first flow channel L1 and the treatment space within the chamber 12communicate with each other through a plurality of first gas dischargeholes described later. The first gas is supplied from the plurality offirst gas discharge holes connected to the first flow channel L1 to thetreatment space of the chamber 12.

A first diaphragm valve is provided between the first flow channel L1and each of the first gas discharge holes to correspond to the first gasdischarge hole. That is, the gas supply system 1 includes a plurality offirst diaphragm valves corresponding to the plurality of first gasdischarge holes. As an example, FIG. 1 shows four first diaphragm valvesDV1 to DV4 corresponding to four first gas discharge holes. The fourfirst diaphragm valves DV1 to DV4 can operate independently with eachother. An example of the first diaphragm valve is an ON/OFF valve. Thedetails of the first diaphragm valve will be described later. The numberof first gas discharge holes may be two or more without being limited tofour. In addition, the plurality of first diaphragm valves are notlimited in number to four, and may be provided to correspond to theplurality of first gas discharge holes.

A first orifice may be provided between the first flow channel L1 andeach of the first gas discharge holes to correspond to the first gasdischarge hole. The first orifice is disposed further upstream than thefirst diaphragm valve. As an example, FIG. 1 shows four first orificesOL1 to OL4. Each of the first diaphragm valves controls a supply timingof the first gas supplied from the outlet of the first orifice to thefirst gas discharge hole. A plurality of first orifices is not limitedin number to four, and may be provided to correspond to the plurality offirst gas discharge holes.

The second flow channel L2 is connected to the second gas source GS2,and is formed inside the upper electrode of the chamber 12 or inside thesidewall of the chamber 12. The second flow channel L2 is a closedspace, and is connected to a plurality of second discharge holesdescribed later. The second gas is supplied from the plurality of seconddischarge holes connected to the second flow channel L2 to the treatmentspace of the chamber 12.

The gas supply system 1 may include a pressure type flow rate controlapparatus FC2. The pressure type flow rate control apparatus FC2 isdisposed on the downstream side of the second gas source GS2 in thesecond main flow channel L20. A primary valve VL4 is provided on theupstream side of the pressure type flow rate control apparatus FC2, anda secondary valve VL5 is provided on the downstream side of the pressuretype flow rate control apparatus FC2. Meanwhile, the flow rate controlapparatus may be a thermal type flow rate control apparatus or a flowrate control apparatus based on other principles without being limitedto the pressure type flow rate control apparatus.

The second gas of the second gas source GS2 has the flow rate andpressure adjusted by the pressure type flow rate control apparatus FC2,and is supplied to the second flow channel L2 of the chamber 12 throughthe supply port IN4.

The gas supply system 1 may include a control valve VL1. The controlvalve VL1 is disposed on the downstream side of the first gas source GS1in the first main flow channel L10. The control valve VL1 is providedupstream of the supply port IN1, and controls the first gas supplied tothe supply port IN1 at a predetermined pressure. The control valve VL1has the same function as that of a control valve included in thepressure type flow rate control apparatus FC2. A first pressure detectorPM1 may be disposed in a flow channel between the control valve VL1 andthe supply port IN1.

As an example, the control valve VL1 controls the flow rate of the firstgas on the basis of the detection result of the first pressure detectorPM1. As a more specific example, a control circuit C1 determines theoperation of the control valve VL1. The control circuit C1 inputs apressure detected by the first pressure detector PM1, and calculates aflow rate at the detected pressure. The control circuit C1 compares aset target flow rate with the calculated flow rate, and determines theoperation of the control valve VL1 so that a difference therebetweendecreases. Meanwhile, the primary valve may be provided between thefirst gas source GS1 and the control valve VL1. The secondary valve maybe provided downstream of the control valve VL1, and upstream of thefirst pressure detector PM1. In addition, the control circuit C1 and thecontrol valve VL1 may be unitized as a unit U1.

The gas supply system 1 may further include a second pressure detectorPM2 that detects the pressure of the first gas exhausted from theexhaust port OT1. In this case, as an example, the control valve VL1controls the flow rate of the first gas on the basis of the detectionresults of the first pressure detector PM1 and the second pressuredetector PM2. More specifically, the pressure of the first gas at thearrangement position of each first orifice is calculated on the basis ofthe detection result of the first pressure detector PM1 and thedetection result of the second pressure detector PM2. The supply timingof the first gas is controlled by each first diaphragm valve on thebasis of the result of calculation of pressure.

The gas supply system 1 may include a temperature detector that detectsthe temperature of the first gas in the first flow channel L1. In thiscase, the control valve VL1 performs flow rate correction using thetemperature detector, similarly to the control valve included in thepressure type flow rate control apparatus FC2. Specifically, the controlvalve VL1 controls the flow rate of the first gas on the basis of thedetection result of the temperature detector.

The first gas of the first gas source GS1 has the flow rate and pressureadjusted by the control valve VL1, and is supplied to the first flowchannel L1 of the chamber 12 through the supply port IN1. Meanwhile, theexhaust port OT1 of the first flow channel L1 may be provided with anexhaust orifice OL9.

The gas supply system 1 includes a controller C2 (an example of a firstcontroller) that brings the control valve VL1 and a plurality of firstdiaphragm valves DV1 to DV4 into operation. The controller C2 is acomputer including a processor, a storage unit, an input device, adisplay device, and the like. The controller C2 inputs a recipe storedin the storage unit, and outputs a signal to the control circuit C1 thatbrings the control valve VL1 into operation. In addition, the controllerC2 inputs the recipe stored in the storage unit, and controls theswitching operations of the plurality of first diaphragm valves DV1 toDV4. In addition, the controller C2 may operate the exhaust apparatus 51through the control circuit C1.

[First Diaphragm Valve]

Since the plurality of first diaphragm valves DV1 to DV4 are configuredto be the same as each other, the first diaphragm valve DV1 will bedescribed below by way example. FIG. 2 is a cross-sectional viewschematically illustrating the first diaphragm valve DV1. The firstdiaphragm valve DV1 is disposed on the first flow channel L1. As shownin FIG. 2 , the first diaphragm valve DV1 includes a lower main body 71and an upper main body 72. A sealing member 74 exhibiting a valvefunction is disposed between the lower main body 71 and the upper mainbody 72. The lower main body 71 has a flow channel for circulating a gasformed therein. The upper main body 72 includes a component that bringsthe sealing member 74 into operation.

The sealing member 74 may be constituted by a member having flexibility.The sealing member 74 may be, for example, an elastic member, adiaphragm, a bellows, or the like.

The lower main body 71 has a flow channel serving as a portion of thefirst flow channel L1 formed therein. As a specific example, the lowermain body 71 has an inlet 71 a and an outlet 71 b, and has an internalflow channel 71 c extending from the inlet 71 a to the outlet 71 b.

An orifice support portion 71 d for supporting the first orifice OL1 isformed within the internal flow channel 71 c. The orifice supportportion 71 d protrudes from the inner wall of the internal flow channel71 c toward the upper main body 72 side (sealing member 74 side) of theinternal flow channel 71 c. The orifice support portion 71 d has aninlet 71 e and an outlet 71 f, and has an internal flow channel 71 gextending from the inlet 71 e to the outlet 71 f. The first orifice OL1is provided on the outlet 71 f of the orifice support portion 71 d. Aseal portion 75 protruding to the upper main body 72 side (sealingmember 74 side) rather than the first orifice OL1 is provided in thevicinity of the first orifice OL1.

The upper main body 72 includes a component that controls a distancebetween the sealing member 74 and the first orifice OL1. As a specificexample, the upper main body 72 includes a cylinder 76, an urging member78 and a driving portion 81.

The cylinder 76 fixedly supports the sealing member 74, and is housedinside the upper main body 72. For example, the cylinder 76 fixes thesealing member 74 to the lower end thereof. The cylinder 76 includes aprotruding portion 76 a of which the diameter is expanded toward theouter side. The cylinder 76 includes a flow channel 76 b therein. A sealmember 79 is provided between the lateral side of the protruding portion76 a and the inner wall of the upper main body 72, and between thelateral side of the cylinder 76 which is located further downward thanthe protruding portion 76 a and the inner wall of the upper main body72. A space 82 is formed by the inner wall of the upper main body 72,the sidewall of the cylinder 76, the lower surface of the protrudingportion 76 a, and the seal member 79. The flow channel 76 b of thecylinder 76 communicates with the space 82.

The urging member 78 elastically urges the cylinder 76 in a direction inwhich the sealing member 74 is pressed against the first orifice OL1.For example, the cylinder 76 is urged against the lower main body 71side (first orifice OL1 side). More specifically, the urging member 78gives an urging force to the upper surface of the protruding portion 76a of the cylinder 76 downward. The sealing member 74 is pressed againstthe first orifice OL1 by the urging member 78 to seal the outlet 73 ofthe first orifice OL1. In this manner, the second flow channel is closedby the action of the urging member 78 (closing control). The urgingmember 78 is constituted by, for example, an elastic body. As a specificexample, the urging member 78 is a spring.

The driving portion 81 moves the cylinder 76 in a direction opposite tothe pressed direction. The driving portion 81 supplies air to the flowchannel 76 b of the cylinder 76, and fills air into the space 82. In acase where the pressure of the air filled into the space 82 becomeslarger than the urging force of the urging member 78, the cylinder 76rises together with the sealing member 74. That is, the sealing member74 is separated from the first orifice OL1 by the driving portion 81. Inthis manner, the second flow channel is opened by the driving portion 81(opening control).

The internal flow channel 71 c of the lower main body 71 has a structurein which the channel is not blocked by the operation of the sealingmember 74. That is, the first flow channel L1 is not blocked by theoperation of the sealing member 74, and is in a state of communicatingat all times. FIG. 3 is a diagram schematically illustrating a lowerstructure of the first diaphragm valve DV1. As shown in FIG. 3 , theinternal flow channel 71 c is formed to surround the periphery of theorifice support portion 71 d. The first gas passes through the lateralportion of the orifice support portion 71 d when the sealing member 74is pressed against the first orifice OL1, and passes through the lateralportion and upper portion of the orifice support portion 71 d when thesealing member 74 is separated from the first orifice Oil. In thismanner, the sealing member 74 realizes switching without influencing thecirculation of the first flow channel L1.

Meanwhile, the above-described first diaphragm valve DV1 is an example,and can be variously changed. For example, the protruding direction ofthe sealing member 74 may be reversed. In addition, the motive power ofthe first diaphragm valve DV1 may be a piezoelectric element.

[Substrate Treatment Apparatus]

As a substrate treatment apparatus (substrate treatment system)including the gas supply system 1, a plasma treatment apparatus of anexemplary embodiment will be described. FIG. 4 is a diagramschematically illustrating a plasma treatment apparatus according to anexemplary embodiment. A plasma treatment apparatus 10 shown in FIG. 4 isa capacitive coupling type plasma treatment apparatus for plasmaetching.

The plasma treatment apparatus 10 includes the chamber 12. The chamber12 has a substantially cylindrical shape. The chamber 12 is constitutedof, for example, aluminum, and has anodic oxidation performed on theinner wall surface thereof. This chamber 12 is grounded by security. Inaddition, a grounded conductor 12 a is mounted on the upper end of thesidewall of the chamber 12 to extend from the sidewall upward. Thegrounded conductor 12 a has a substantially cylindrical shape. Inaddition, a carrying-in outlet 12 g of a substrate (hereinafter,referred to as a “wafer W”) is provided on the sidewall of the chamber12, and this carrying-in outlet 12 g is configured to be capable ofbeing switched by a gate valve 54.

A support portion 14 of a substantially cylindrical shape is provided onthe bottom of the chamber 12. The support portion 14 is constituted of,for example, an insulating material. The support portion 14 extends fromthe bottom of the chamber 12 in a vertical direction, within the chamber12. In addition, a placing table PD is provided within the chamber 12.The placing table PD is supported by the support portion 14.

The placing table PD holds the wafer W on the upper surface thereof. Theplacing table PD includes a lower electrode LE and an electrostaticchuck ESC. The lower electrode LE includes a first plate 18 a and asecond plate 18 b. The first plate 18 a and the second plate 18 b areconstituted of a metal such as, for example, aluminum, and have asubstantially discoid shape. The second plate 18 b is provided on thefirst plate 18 a, and is electrically connected to the first plate 18 a.

The electrostatic chuck ESC is provided on the second plate 18 b. Theelectrostatic chuck ESC has a structure in which an electrode which is aconductive film is disposed between a pair of insulating layers orinsulating sheets. A direct-current power source 22 is electricallyconnected to the electrode of the electrostatic chuck ESC through aswitch 23. This electrostatic chuck ESC adsorbs the wafer W using anelectrostatic force such as a Coulomb's force generated by adirect-current voltage from the direct-current power source 22. Thereby,the electrostatic chuck ESC can hold the wafer W.

A focus ring FR is disposed on the peripheral edge of the second plate18 b to surround the edge of the wafer W and the electrostatic chuckESC. The focus ring FR improves the uniformity of plasma treatment. Thefocus ring FR may be constituted of a material such as, for example,silicon, quartz, or SiC.

A refrigerant flow channel 24 is provided within the second plate 18 b.The refrigerant flow channel 24 constitutes a temperature-adjustingmechanism. A refrigerant is supplied to the refrigerant flow channel 24from a chiller unit provided outside the chamber 12 through piping 26 a.The refrigerant supplied to the refrigerant flow channel 24 is returnedto the chiller unit through the piping 26 b. In this manner, therefrigerant is supplied to the refrigerant flow channel 24 to becirculated. The temperature of this refrigerant is controlled, and thusthe temperature of the wafer W supported by the electrostatic chuck ESCis controlled.

In addition, the plasma treatment apparatus 10 is provided with a gassupply line 28. The gas supply line 28 supplies a heat-transfer gas froma heat-transfer gas supply mechanism, for example, a He gas between theupper surface of the electrostatic chuck ESC and the rear surface of thewafer W.

In addition, the plasma treatment apparatus 10 is provided with a heaterHT which is a heating element. The heater HT is buried within, forexample, the second plate 18 b. A heater power source HP is connected tothe heater HT. By supplying power supplied from the heater power sourceHP to the heater HT, the temperature of the placing table PD isadjusted, and the temperature of the wafer W placed on the placing tablePD is adjusted. Meanwhile, the heater HT may be built into theelectrostatic chuck ESC.

In addition, the plasma treatment apparatus 10 includes an upperelectrode 30. The upper electrode 30 is a ceiling member constitutingthe ceiling of the chamber 12. The upper electrode 30 is disposed to beopposite to the placing table PD, on the upper portion of the placingtable PD. The lower electrode LE and the upper electrode 30 are providedsubstantially in parallel to each other. A treatment space S forperforming plasma treatment on the wafer W is provided between the upperelectrode 30 and the placing table PD.

The upper electrode 30 is supported on the upper portion of the chamber12 with an insulating shielding member 32 interposed therebetween. In anexemplary embodiment, the upper electrode 30 may be configured such thata distance in a vertical direction from the upper surface of the placingtable PD, that is, a wafer placement surface is variable. The upperelectrode 30 may include a top plate 34 and a support 36. The top plate34 faces the treatment space S, and the top plate 34 is provided with aplurality of gas discharge holes. The gas discharge hole includes afirst gas discharge hole and a second gas discharge hole. Meanwhile, inFIG. 4 , only the second gas discharge hole 34 a is shown. This topplate 34 may be constituted of silicon or a silicon oxide.Alternatively, the top plate 34 may be formed by coating a conductive(for example, aluminum) base material with ceramics. The details of theupper electrode 30 will be described later.

The support 36 detachably supports the top plate 34, and may beconstituted of a conductive material such as, for example, aluminum.This support 36 may have a water-cooling structure. The first flowchannel L1 and the second flow channel L2 are provided inside thesupport 36. Meanwhile, FIG. 4 shows only the second flow channel L2. Thefirst main flow channel L10 of the gas supply system 1 is connected tothe first flow channel L1. The second main flow channel L20 of the gassupply system 1 is connected to the second flow channel L2. The detailsof the first flow channel L1 and the second flow channel L2 will bedescribed later.

A plurality of communication holes for connecting the first flow channelL1 and the plurality of gas discharge holes extending downward of thefirst flow channel L1 are formed in the support 36. A plurality ofcommunication holes 36 b for connecting the second flow channel L2 and aplurality of second gas discharge holes 34 a extending downward of thesecond flow channel L2 are formed in the support 36. The upper electrode30 having such a configuration constitutes a shower head SH.

In addition, in the plasma treatment apparatus 10, a deposit shield 46is detachably provided along the inner wall of the chamber 12. Thedeposit shield 46 is also provided on the outer circumference of thesupport portion 14. The deposit shield 46 is used for preventingby-products (deposits) of plasma treatment from being attached to thechamber 12, and may be formed by covering an aluminum material withceramics such as Y₂O₃.

An exhaust plate 48 is provided on the bottom side of the chamber 12,and between the support portion 14 and the sidewall of the chamber 12.The exhaust plate 48 may be formed by covering, for example, an aluminummaterial with ceramics such as Y₂O₃. A large number of through-holes areformed in the exhaust plate 48. The lower portion of this exhaust plate48 and the chamber 12 are provided with an exhaust port 12 e. An exhaustapparatus 50 and an exhaust apparatus 51 are connected to the exhaustport 12 e through an exhaust pipe 52. In an exemplary embodiment, theexhaust apparatus 50 is a turbo-molecular pump, and the exhaustapparatus 51 is a dry pump. The exhaust apparatus 50 is provided furtherupstream than the exhaust apparatus 51 with respect to the chamber 12.The exhaust flow channel EL of the gas supply system 1 is connected topiping between the exhaust apparatus 50 and the exhaust apparatus 51.The exhaust flow channel EL is connected between the exhaust apparatus50 and the exhaust apparatus 51, and thus the backflow of a gas from theexhaust flow channel EL into the chamber 12 is suppressed.

In addition, the plasma treatment apparatus 10 further includes a firstradio-frequency power source 62 and a second radio-frequency powersource 64. The first radio-frequency power source 62 generates a firstradio frequency for plasma generation, and generates a frequency of 27to 100 MHz or a radio frequency of 40 MHz in an example. The firstradio-frequency power source 62 is connected to the lower electrode LEwith a matching device 66 interposed therebetween. The matching device66 includes a circuit for matching output impedance of the firstradio-frequency power source 62 with input impedance on the load side(lower electrode LE side).

The second radio-frequency power source 64 generates a second radiofrequency for attracting ions to the wafer W, that is, a radio frequencyfor a bias, and generates a frequency in a range of 400 kHz to 13.56MHz, or a second radio frequency of 3.2 MHz in an example. The secondradio-frequency power source 64 is connected to the lower electrode LEwith a matching device 68 interposed therebetween. The matching device68 includes a circuit for matching output impedance of the secondradio-frequency power source 64 with input impedance on the load side(lower electrode LE side).

In addition, in an exemplary embodiment, the controller C2 shown in FIG.1 controls each portion of the plasma treatment apparatus 10 to performplasma treatment executed in plasma treatment apparatus 10.

This plasma treatment apparatus 10 can generate plasma by exciting a gassupplied into the chamber 12. The wafer W can be processed by activespecies. In addition, while the second gas is supplied by the gas supplysystem 1, for example, at a second flow rate, the first gas can besupplied into the chamber 12 intermittently with good responsiveness ata first flow rate smaller than the second flow rate. Therefore, it ispossible to enhance the throughput of a process of alternatelyperforming different plasma treatments on the wafer W.

[Details of Upper Electrode]

FIG. 5 is a schematic cross-sectional view of the upper electrode 30 inFIG. 4 . As shown in FIG. 5 , the first flow channel L1 and the secondflow channel L2 that extend in a horizontal direction are providedinside the support 36 of the upper electrode 30. The first flow channelL1 is located below the second flow channel L2.

A plurality of communication holes 36 c for connecting the first flowchannel L1 and a plurality of first gas discharge holes 34 b extendingdownward of the first flow channel L1 are formed in the support 36. Thefirst orifice OL1 and first diaphragm valve DV1 are provided between thefirst flow channel L1 and the first gas discharge hole 34 b of thesupport 36. The first diaphragm valve DV1 in FIG. 5 protrudes thesealing member 74 of the first diaphragm valve DV1 in FIG. 2 in anopposite direction, but has the same function. The first gas flowingthrough the first flow channel L1 is supplied to the treatment spacethrough the outlet of the first orifice OL1, the communication hole 36c, and the first gas discharge hole 34 b when the first diaphragm valveDV1 is opened. Other first gas discharge holes 34 b also have the sameconfiguration. Meanwhile, the support 36 is provided with a temperaturedetector TM1 in order for the control valve VL1 to perform flow ratecorrection.

The plurality of communication holes 36 b for connecting the second flowchannel L2 and the plurality of second gas discharge holes 34 aextending downward of the second flow channel L2 are formed in thesupport 36. The second gas is supplied through the supply port IN4, andis supplied to the treatment space through the plurality ofcommunication holes 36 b and the plurality of second gas discharge holes34 a.

FIG. 6 is a schematic diagram when the first flow channel L1 is seen ina plan view. FIG. 6 shows three first flow channels L1 as an example. Aplurality of orifices OL (first orifices) are provided in the first flowchannel L1 to correspond to the plurality of first gas discharge holes34 b.

As an example, the support 36 has three regions outside from the centerthereof. The most central region of the support is a third region R3, asecond region R2 is located to surround the third region R3, and a firstregion R1 is located to surround the second region R2. The first flowchannel L1 is formed in each of the regions. For example, in the firstregion R1, the first flow channel L1 extends from the supply port IN1 tothe exhaust port OT1. In the second region R2, the first flow channel L1extends from a supply port IN2 to an exhaust port OT2. In the thirdregion R3, the first flow channel L1 extends from a supply port IN3 toan exhaust port OT3. Meanwhile, the number of regions included in thesupport 36 may be one or plural without being limited to three.

[Control of Controller]

The controller C2 inputs a recipe stored in the storage unit, andcontrols the switching operations of the plurality of first diaphragmvalves. Since the first flow channel L1 extends from a supply port to anexhaust port, there is a concern that the pressure difference of thefirst gas occurs between a first gas discharge hole close to the supplyport and a first gas discharge hole close to the exhaust port, dependingon the length of the first flow channel L1. In this case, there is aconcern that the amounts of supply of the first gas to the treatmentspace are different from each other for each first gas discharge hole.For this reason, the exhaust port OT1 of the first flow channel L1 isprovided with the exhaust orifice OL9. Thereby, a few errors arepresent, but the pressure of the first flow channel L1 can be madesubstantially uniform without being dependent on its position.

However, in a case where it is necessary to eliminate the error ofpressure dependent on a position, or a case where the gas supply system1 does not include the exhaust orifice OL9, the controller C2 performscontrol for canceling a pressure distribution dependent on a position.The controller C2 calculates (predicts) the pressure of the first gas atthe arrangement position of each first orifice, on the basis of thecomparison of the detection result of the first pressure detector PM1provided upstream of the supply port with the detection result of thesecond pressure detector PM2 provided downstream of the exhaust port.

FIG. 7 is a graph illustrating a relationship between a control pressureand the position of an orifice in the first flow channel L1. Thehorizontal axis is the position of the orifice in a case where acoordinate axis is provided in the extending direction of the first flowchannel L1, and the vertical axis is a control pressure. In the drawing,an example is shown in which sixteen orifices are disposed. The controlpressure is a pressure targeted by the controller C2. As shown in FIG. 7, the control pressure in the supply port IN1 can be set to a pressuredetected by the first pressure detector PM1. The control pressure in theexhaust port OT1 can be set to a pressure detected by the secondpressure detector PM2. The controller C2 approximates a control pressurecorresponding to a position within the first flow channel L1 as a linearpressure passing through the control pressure in the supply port IN1 andthe control pressure in the exhaust port OT1. Since a position at whichan orifice is disposed is well-known, the controller C2 can calculatethe pressure of the first gas at the arrangement position of each firstorifice, using the graph shown in FIG. 7 . The controller C2 performsthe switching control of the first diaphragm valve so that the flow rateof the first gas is set to a target flow rate written in a recipe, onthe basis of the calculated pressure.

[Gas Supply Method] Next, a gas supply method performed by the gassupply system 1 will be described. The gas supply method may be realizedby components of the gas supply system 1 being operated by thecontroller C2. FIG. 8 is a flow diagram of a gas supply method accordingto the first exemplary embodiment.

Initially, the controller C2 supplies the second gas from the second gassource GS2 to the second flow channel L2. Thereby, the second gas issupplied from the second gas discharge hole 34 a to the treatment space(step S10).

Subsequently, the controller C2 supplies the first gas from the firstgas source GS1 to the first flow channel L1. In this case, thecontroller C2 sets the first diaphragm valve DV1 to be closed (stepS12). Thereby, the first gas circulates through the first flow channelL1 at a predetermined flow rate, and is exhausted from the exhaust portOT1. The first flow channel L1 enters a state where the first gas havinga predetermined target pressure circulates in a state where the supplyof the first gas to the chamber 12 is stopped.

Subsequently, the controller C2 sets the first diaphragm valve DV1 to beopened in a state where the first gas is circulated at a predeterminedflow rate in the first flow channel L1 (step S14). Thereby, the firstgas is supplied from the first gas discharge hole 34 b to the treatmentspace.

Steps S12 and S14 are repeated if necessary. In a case where all theprocesses are terminated, the controller C2 sets the secondary valve VL5to be closed, and sets the first diaphragm valve DV1 to be closed. Inthis manner, the first gas can be added to the second gas by controllingswitching of the first diaphragm valve DV1.

[Conclusion of First Exemplary Embodiment]

In the gas supply system 1, the first gas is supplied from the firstflow channel L1 through the plurality of first gas discharge holes 34 bto the treatment space S, and the second gas is supplied from the secondflow channel L2 through the plurality of second gas discharge holes 34 ato the treatment space S. In this manner, the first gas and the secondgas are supplied to the treatment space S without being merged with eachother. Therefore, the gas supply system 1 can save a time which will betaken until the merged gas reaches the chamber 12, as compared with acase where the first gas and the second gas are merged with each otherbefore these gases are supplied to the chamber 12. Therefore, the gassupply system 1 is an excellent response speed. In addition, each of thefirst diaphragm valves DV1 to DV4 is disposed between the first flowchannel L1 and the first gas discharge hole 34 b, that is, in thevicinity of the treatment space S. Therefore, the gas supply system 1can supply and control the first gas with good responsiveness throughthe first diaphragm valves DV1 to DV4, and can perform high-speedswitching between a case where only the second gas is supplied to thetreatment space S and a case where a mixed gas of the first gas and thesecond gas is supplied to the treatment space S. Thus, the gas supplysystem 1 can improve the response speed of a process gas, and alsofurther improve the switching speed of the process gas. Further, the gassupply system 1 can control the supply and stop of the first gas foreach first gas discharge hole.

In addition, in the gas supply system 1, the first gas is supplied tothe first flow channel L1 at a predetermined pressure by the controlvalve VL1, and circulates from the supply port IN1 of the first flowchannel L1 to the exhaust port OT1. The first gas is supplied from theoutlets of the first orifices OL1 to OL4 to the first gas discharge hole34 b by switching of the first diaphragm valves DV1 to DV4. Therefore,the gas supply system 1 can stabilize the pressure of the first flowchannel L1 in the entire flow channel, and branch the first gas fromeach of a plurality of points of the first flow channel L1 of which thepressure is stabilized. Thus, the gas supply system 1 can reduce apressure error for each first gas discharge hole 34 b. In addition, thegas supply system 1 includes the first orifices OL1 to OL4 correspondingto the first gas discharge hole 34 b, and thus can reduce a fluctuationin pressure within the first flow channel L1 due to switching of thefirst diaphragm valves DV1 to DV4.

In addition, the gas supply system 1 can predict the pressure of thefirst gas at the arrangement position of each of the first orifices OL1to OL4, and thus can improve the accuracy of the flow rate of the firstgas supplied from each first gas discharge hole 34 b.

In addition, the gas supply system 1 includes the exhaust orifice OL9downstream of the exhaust port OT1, and thus can reduce the differentialpressure of the first gas dependent on a position within the first flowchannel L1.

In addition, the gas supply system 1 can adjust a flow rate inconsideration of a change in the flow rate of the first gas with achange in temperature, using the temperature detector TM1 that detectsthe temperature of the first gas in the first flow channel L1.

In addition, the gas supply method can continue to supply the secondgas, for example, as a main gas of a process to the treatment space, andto intermittently supply the first gas, for example, as an additive gasat high speed to the treatment space. Therefore, the gas supply methodcan improve the response speed of a process gas, and to further improvethe switching speed of the process gas.

Second Exemplary Embodiment

A gas supply system 1A according to a second exemplary embodiment isdifferent from the gas supply system 1 according to the first exemplaryembodiment, in the operation of the controller C2, and in that a flowrate control apparatus is included instead of the control circuit C1 andthe control valve VL1, the first flow channel L1 does not have anexhaust port, an orifice and a diaphragm valve are disposed in thesecond flow channel L2 to correspond to the second gas discharge hole 34a, and each of gases supplied to the first flow channel L1 and thesecond flow channel L2 is a mixed gas. The other points are the same aseach other. In the second exemplary embodiment, a description will begiven with a focus on differences from the first exemplary embodiment,and a repeated description will not be given.

[Outline of Gas Supply System]

FIG. 9 is a schematic diagram of the gas supply system 1A according tothe second exemplary embodiment. FIG. 9 shows the gas supply system 1Athat supplies gases to a treatment space within the chamber 12 (anexample of a treatment container) of the substrate treatment apparatus.The gas supply system 1A includes a first gas box CG1 and a second gasbox CG2. The first gas box CG1 has a plurality of gas sources includingthe first gas source GS1. As an example, the first gas box CG1 includesthe first gas source GS1, a third gas source GS3, a fourth gas sourceGS4, and a fifth gas source GS5, but there is no limitation thereto. Thesecond gas box CG2 has a plurality of gas sources including the secondgas source GS2. As an example, the second gas box CG2 includes thesecond gas source GS2, a sixth gas source GS6, a seventh gas source GS7,and an eighth gas source GS8, but there is no limitation thereto.

The first gas box CG1 supplies a first mixed gas obtained from aplurality of gas sources to the first flow channel L1. The first gas boxCG1 is connected to the first flow channel L1 by the first main flowchannel L10. The first main flow channel L10 connects the first gas boxCG1 and the first flow channel L1 of the chamber 12 through a supplyport IN5. A pressure type flow rate control apparatus FC1 (an example ofa first flow rate controller) is provided between the first gas box CG1and the first flow channel L1. A primary valve VL2 is provided on theupstream side of the pressure type flow rate control apparatus FC1, anda secondary valve VL3 and a third pressure detector PM3 are provided onthe downstream side of the pressure type flow rate control apparatusFC1. Meanwhile, the flow rate control apparatus may be a thermal typeflow rate control apparatus or a flow rate control apparatus based onother principles without being limited to the pressure type flow ratecontrol apparatus.

The second gas box CG2 supplies a second mixed gas obtained from aplurality of gas sources to the second flow channel L2. The second gasbox CG2 is connected to the second flow channel L2 by the second mainflow channel L20. The second main flow channel L20 connects the secondgas box CG2 and the second flow channel L2 of the chamber 12 through asupply port IN6. A pressure type flow rate control apparatus FC2 (anexample of a second flow rate controller) is provided between the secondgas box CG2 and the second flow channel L2. A primary valve VL4 isprovided on the upstream side of the pressure type flow rate controlapparatus FC2, and a secondary valve VL5 and a fourth pressure detectorPM4 are provided on the downstream side of the pressure type flow ratecontrol apparatus FC2. Meanwhile, the flow rate control apparatus may bea thermal type flow rate control apparatus or a flow rate controlapparatus based on other principles without being limited to thepressure type flow rate control apparatus.

The first flow channel L1 is connected to the first gas box CG1, and isformed inside the upper electrode (an example of the ceiling) of thechamber 12, or inside the sidewall of the chamber 12. The first flowchannel L1 is a closed space to which the first mixed gas is supplied.The first flow channel L1 and the treatment space within the chamber 12communicate with each other through the plurality of first gas dischargeholes 34 b. the first mixed gas is supplied from the plurality of firstgas discharge holes 34 b connected to the first flow channel L1 to thetreatment space of the chamber 12. The first diaphragm valves DV1 to DV4are provided between the first flow channel L1 and the first gasdischarge hole 34 b to correspond to the first gas discharge hole 34 b.Meanwhile, the number of first diaphragm valves is not limited to four.

The second flow channel L2 is connected to the second gas box CG2, andis formed inside the upper electrode (an example of the ceiling) of thechamber 12, or inside the sidewall of the chamber 12. The second flowchannel L2 is a closed space to which the second mixed gas is supplied.The second flow channel L2 and the treatment space within the chamber 12communicate with each other through the plurality of second gasdischarge holes 34 a. The second mixed gas is supplied from theplurality of second gas discharge holes 34 a connected to the secondflow channel L2 to the treatment space of the chamber 12. Seconddiaphragm valves DV5 to DV8 are provided between the second flow channelL2 and the second gas discharge hole 34 a to correspond to the secondgas discharge hole 34 a. Meanwhile, the number of second diaphragmvalves is not limited to four.

The controller C2 (an example of a second controller) is different fromthe controller C2 of the first exemplary embodiment, in that theplurality of first diaphragm valves DV1 to DV4 and the plurality ofsecond diaphragm valves DV5 to DV8 are brought into operation. Thecontroller C2 brings each of the first diaphragm valves DV1 to DV4 intooperation so that the flow rate of the first mixed gas within the firstflow channel L1 is distributed and controlled for each first gasdischarge hole 34 b. The controller C2 brings each of the seconddiaphragm valves DV5 to DV8 into operation so that the flow rate of thesecond mixed gas within the second flow channel L2 is distributed andcontrolled for each second gas discharge hole 34 a.

[Diaphragm Valve and Substrate Treatment Apparatus]

The configuration diaphragm valve is the same as that of the firstexemplary embodiment. Meanwhile, in the second exemplary embodiment, thedriving source of a diaphragm valve is a piezoelectric element. Inaddition, a substrate treatment apparatus to which the gas supply system1A is applied is different from that of the first exemplary embodiment,in only the structure of the upper electrode.

[Details of Upper Electrode]

FIG. 10 is a schematic cross-sectional view of an upper electrode 30A ofthe gas supply system 1A according to the second exemplary embodiment.As shown in FIG. 10 , the first flow channel L1 and the second flowchannel L2 that extend in a horizontal direction are provided inside thesupport 36 of the upper electrode 30A. The first flow channel L1 islocated below the second flow channel L2.

A plurality of communication holes 36 c for connecting the first flowchannel L1 and a plurality of first gas discharge holes 34 b extendingdownward of the first flow channel L1 are formed in the support 36. Thefirst diaphragm valve DV1 is provided between the first flow channel L1and the first gas discharge hole 34 b of the support 36. The first mixedgas flowing through the first flow channel L1 is supplied to thetreatment space through the communication hole 36 c and the first gasdischarge hole 34 b when the first diaphragm valve DV1 is opened. Otherfirst gas discharge holes 34 b also have the same configuration.

A plurality of communication holes 36 b for connecting the second flowchannel L2 and a plurality of second gas discharge holes 34 a extendingdownward of the second flow channel L2 are formed in the support 36. Asecond diaphragm valve DV5 is provided between the second flow channelL2 and the second gas discharge hole 34 a of the support 36. The secondmixed gas flowing through the second flow channel L2 is supplied to thetreatment space through the communication hole 36 b and the second gasdischarge hole 34 a when the second diaphragm valve DV5 is opened. Othersecond gas discharge holes 34 a also include the same configuration.

FIG. 11 is a schematic diagram when the first flow channel L1 and thesecond flow channel L2 are seen in a plan view. In FIG. 11 , the firstflow channel L1 and the second flow channel L2 extend from the center ofthe support 36 toward the outer side. The first flow channel L1 and thesecond flow channel L2 are alternately disposed in a radial direction.The supply port IN5 of the first flow channel L1 and the supply port IN6of the second flow channel L2 are provided on the central side of thesupport 36. FIG. 11 shows eight first flow channels L1 and eight secondflow channels L2 as an example. The first flow channel L1 and the secondflow channel L2 are provided with a plurality of diaphragm valves DV tocorrespond to the plurality of first gas discharge holes 34 b.

[Control of Controller]

The controller C2 inputs a recipe stored in the storage unit, andcontrols the switching operations of the plurality of first diaphragmvalves DV1 to DV4 and the plurality of second diaphragm valves DV5 toDV8. The controller C2 controls the degrees of opening of the pluralityof first diaphragm valves DV1 to DV4 on the basis of a relationshipbetween a flow rate, a pressure and the degree of valve opening acquiredin advance for each first gas discharge hole 34 b, a measurement resultof the third pressure detector PM3, and a target flow rate which is setfor each first gas discharge hole 34 b. Similarly, the controller C2controls the degrees of opening of the plurality of second diaphragmvalves DV5 to DV8 on the basis of a relationship between a flow rate, apressure and the degree of valve opening acquired in advance for eachsecond gas discharge hole 34 a, a measurement result of the fourthpressure detector PM4, and a target flow rate which is set for eachsecond gas discharge hole 34 a.

FIG. 12 is a graph illustrating a relationship between a pressure and aflow rate for each discharge hole. The horizontal axis is a flow rate,and the vertical axis is a pressure. In FIG. 12 , graphs GL1 to GL5acquired in advance with respect to five discharge holes are disclosed.As shown in FIG. 12 , the relationships between a pressure and a flowrate are different from each other for each discharge hole.

FIG. 13 is a graph illustrating a relationship between the degree ofpiezoelectric opening and a flow rate for each discharge hole. Thehorizontal axis is a flow rate, and the vertical axis is the degree ofpiezoelectric opening. FIG. 13 shows graphs GL1 to GL5 acquired inadvance with respect to five discharge holes. As shown in FIG. 13 , therelationships between the degree of piezoelectric opening and a flowrate are different from each other for each discharge hole.

The controller C2 acquires a relationship between a flow rate, apressure and the degree of valve opening for each discharge hole, usingthe relationship between a flow rate and a pressure and the relationshipbetween a flow rate and the degree of valve opening which are shown inFIGS. 12 and 13 . The controller C2 determines the degrees of opening ofthe plurality of first diaphragm valves DV1 to DV4 by referring to therelationship between a flow rate, a pressure and the degree of valveopening, on the basis of the measurement result of a pressure and thetarget flow rate which is set for each first gas discharge hole 34 b. Bysuch a determination, the controller C2 can distribute and control amixed gas supplied to a closed space from each gas discharge hole, inconsideration of a differential pressure within a flow channel.

[Gas Supply Method]

Next, a gas supply method performed by the gas supply system 1A will bedescribed. The gas supply method may be realized by components of thegas supply system 1A being operated by the controller C2. FIG. 14 is aflow diagram of the gas supply method according to the second exemplaryembodiment. Meanwhile, the first diaphragm valve and the seconddiaphragm valve are closed at the time of start.

Initially, the controller C2 supplies the first mixed gas having apredetermined flow rate from the first gas box CG1 to the first flowchannel L1, sets the first diaphragm valve to be opened, and sets thesecond diaphragm valve to be closed (step S20). The degree of opening ofthe first diaphragm valve is controlled for each first gas dischargehole 34 b. Thereby, the first mixed gas having a predetermined flow rateis distributed for each first gas discharge hole 34 b, and is suppliedto the treatment space S.

Next, the controller C2 supplies the second mixed gas having apredetermined flow rate from the second gas box CG2 to the second flowchannel L2, sets the second diaphragm valve to be opened, and sets thefirst diaphragm valve to be closed (step S22). The degree of opening ofthe second diaphragm valve is controlled for each second gas dischargehole 34 a. Thereby, the second mixed gas having a predetermined flowrate is distributed for each second gas discharge hole 34 a, and issupplied to the treatment space S.

Steps S20 and S22 are repeated if necessary. In a case where all theprocesses are terminated, the controller C2 closes the secondary valveVL5, the first diaphragm valve and the second first diaphragm valve. Inthis manner, it is possible to perform high-speed switching between thefirst mixed gas and the second mixed gas by controlling switching of thediaphragm valves.

[Degree of Piezoelectric Opening]

Next, control of the gas flow rate of a diaphragm valve using apiezoelectric element will be described in detail. FIGS. 15A and 15B arean example of a relationship between the amount of piezoelectricdisplacement (the degree of piezoelectric opening) of a piezoelectricelement and an applied voltage. A first piezoelectric element (FIG. 15A)is fully opened (set to a flow rate of 100%) at an applied voltage of120 V, and is closed (set to a flow rate of 0%) at an applied voltage of0 V. Similarly to the first piezoelectric element, a secondpiezoelectric element (FIG. 15B) is also fully opened (set to a flowrate of 100%) at an applied voltage of 120 V, and is closed (set to aflow rate of 0%) at an applied voltage of 0 V. However, in a case wherea flow rate is set to X % (100>X>1), the first piezoelectric elementrequires an applied voltage of 75 V, and the second piezoelectricelement requires an applied voltage of 60 V. In addition, in a casewhere a flow rate is set to 1%, the first piezoelectric element requiresan applied voltage of 50 V, and the second piezoelectric elementrequires an applied voltage of 20 V. In this manner, the piezoelectricelement has a variation in an applied voltage for reaching the amount ofpiezoelectric displacement for each element.

FIG. 16A is a graph illustrating a relationship between a flow rate andan applied voltage, and shows a graph SM1 relating to the firstpiezoelectric element A and a graph SM2 relating to the secondpiezoelectric element. The horizontal axis is an applied voltage, andthe vertical axis is a flow rate. As shown in FIG. 16A, the relationshipbetween an applied voltage and a flow rate is a hysteresis together withthe first piezoelectric element and the second piezoelectric element. Onthe other hand, FIG. 16B is a graph illustrating a relationship betweena flow rate and the amount of piezoelectric displacement, and shows agraph SM1 relating to the first piezoelectric element A and a graph SM2relating to the second piezoelectric element. The horizontal axis is theamount of piezoelectric displacement, and the vertical axis is a flowrate. As shown in FIG. 16B, the relationship between the amount ofpiezoelectric displacement and a flow rate is linear together with thefirst piezoelectric element and the second piezoelectric element.Therefore, control of a piezoelectric element using the amount ofpiezoelectric displacement as a control parameter rather than control ofa piezoelectric element using the applied voltage as a control parameterleads to excellent controllability and an error not being likely tooccur. Therefore, in a case where switching control of a diaphragm isperformed, the controller C2 does not perform switching control of adiaphragm using the applied voltage as a control parameter, and performsswitching control of a diaphragm using the amount of piezoelectricdisplacement as a control parameter. Meanwhile, the amount ofpiezoelectric displacement can be monitored using a well-known sensor.

[Self-Diagnosis Function]

The controller C2 may have a function of determining whether the flowrate of a diaphragm valve is a control target. FIG. 17 is an example ofa configuration in which a flow rate self-diagnosis is performed. InFIG. 17 , a diaphragm valve 201 is disposed on a third flow channel L3.A pressure detector PM8, a temperature detector TM8, an orifice 203 anda secondary valve 202 are disposed downstream of the diaphragm valve201. Here, a primary valve 200 and a pressure detector PM9 are disposedupstream of the diaphragm valve 201. The pressure detector PM9 isdisposed, and thus it is possible to measure the primary-side pressureof the diaphragm valve 201. Therefore, it is possible to store theamount of piezoelectric displacement and the actual flow rate of thediaphragm valve 201 in association therewith. The controller C2 comparesstored data with an actual measured value, and determines that a flowrate cannot be correctly controlled in a case where a relationshipbetween the amount of piezoelectric displacement and the actual flowrate deviates from an allowable range. In this manner, the controller C2can perform a self-diagnosis on a flow rate. In addition, the controllerC2 can also determine that a piezoelectric element deteriorates with agein a case where it is determined that a flow rate cannot be correctlycontrolled. Therefore, the controller C2 can also predict a replacementtiming of a piezoelectric element.

[Conclusion of Second Exemplary Embodiment]

In the gas supply system 1A, the first mixed gas including the first gasis controlled by the pressure type flow rate control apparatus FC1 to apredetermined flow rate, and is supplied to the first flow channel L1.Each of the first diaphragm valves DV1 to DV4 is operated by thecontroller C2. Thereby, the first mixed gas having a predetermined flowrate within the first flow channel L1 is distributed and controlled foreach first gas discharge hole 34 b. The second mixed gas including thesecond gas is controlled by the pressure type flow rate controlapparatus FC2 to a predetermined flow rate, and is supplied to thesecond flow channel L2. Each of the second diaphragm valves DV5 to DV8is operated by the controller C2. Thereby, the second mixed gas withinthe second flow channel L2 is distributed and controlled for each secondgas discharge hole 34 a. In this manner, the gas supply system candistribute and control a flow rate for each discharge hole.

The gas supply system 1A can control the degrees of opening of the firstdiaphragm valves DV1 to DV4 and the second diaphragm valves DV5 to DV8,on the basis of the relationship between a flow rate, a pressure and thedegree of valve opening, the measurement result of a pressure, and thetarget value.

In addition, the controller C2 may control the degrees of opening of thefirst diaphragm valves DV1 to DV4 and the degrees of opening of thesecond diaphragm valves DV5 to DV8 using the amount of piezoelectricdisplacement as a parameter. In this case, the gas supply system cansuppress control errors of the degrees of opening of the first diaphragmvalves DV1 to DV4 and the second diaphragm valves DV5 to DV8, ascompared with a case where a control voltage is used as a parameter.

In addition, according to the gas supply method of the second exemplaryembodiment, it is possible to improve the response speed of a processgas, and to further improve the switching speed of the process gas.

As stated above, various exemplary embodiments have been described, butvarious modifications can be made without being limited to theabove-described exemplary embodiments. For example, the respectiveexemplary embodiments may be combined. In addition, the above-describedsubstrate treatment apparatus is a capacitive coupling type plasmatreatment apparatus, but the substrate treatment apparatus may be aninductively coupled plasma treatment apparatus, or any plasma treatmentapparatus such as a plasma treatment apparatus using surface waves ofmicro waves. In addition, an example has been described in which thefirst flow channel L1 and the second flow channel L2 are formed on theupper electrode, but the first flow channel L1 and the second flowchannel L2 may be formed inside the sidewall of a chamber.

EXAMPLES

Hereinafter, examples and comparative examples carried out by theinventor will be set forth to describe the above effects, but thepresent disclosure is not limited the following examples.

(Improvement of Flow Rate Control Responsiveness)

The flow rate control responsiveness of a diaphragm valve was verified.As an example, a flow rate was simulated using the amount ofpiezoelectric displacement as a control parameter. As a comparativeexample, a flow rate was simulated using an applied voltage as a controlparameter. FIGS. 18A and 18B show results. FIGS. 18A and 18B are graphsillustrating a relationship between a flow rate and a time in thecomparative example and the example. FIG. 18A is the comparativeexample. The horizontal axis is a time, and the vertical axis is a flowrate or an applied voltage. A graph G1 is a control target value, agraph G2 is an applied voltage value, and a graph G3 is a flow rate.FIG. 18B is the example. The horizontal axis is a time, and the verticalaxis is a flow rate or the degree of valve opening (the amount ofpiezoelectric displacement). A graph G1 is a control target value, agraph G2 is the degree of valve opening, and a graph G3 is a flow rate.When the example and the comparative example are compared with eachother, it is confirmed that the rise of the graph G3 is faster in theexample than in the comparative example. Therefore, it is confirmed thatthe responsiveness of flow rate control is improved by using a controlparameter as the degree of valve opening (the amount of piezoelectricdisplacement).

(Enhancement of Undershoot)

Undershoot during flow rate control of a diaphragm valve was verified.As the example, a flow rate was simulated using the amount ofpiezoelectric displacement as a control parameter. As the comparativeexample, a flow rate was simulated using an applied voltage as a controlparameter. FIGS. 19A and 19B show results. FIGS. 19A and 19B are graphsillustrating a relationship between a flow rate and a time in thecomparative example and the example. FIG. 19A is the comparativeexample. The horizontal axis is a time, and the vertical axis is a flowrate or an applied voltage. A graph G1 is a control target value, agraph G2 is an applied voltage value, and a graph G3 is a flow rate.FIG. 19B is the example. The horizontal axis is a time, and the verticalaxis is a flow rate or the degree of valve opening (the amount ofpiezoelectric displacement). A graph G1 is a control target value, agraph G2 is the degree of valve opening, and a graph G3 is a flow rate.When the example and the comparative example are compared with eachother, it is confirmed that the graph G3 is not undershot during fall inthe example rather than the comparative example. Therefore, it isconfirmed that undershoot is enhanced by using a control parameter asthe degree of valve opening (the amount of piezoelectric displacement).

What is claimed is:
 1. A gas supply system configured to supply a gas toa treatment space within a treatment container of a substrate treatmentapparatus, the system comprising: a first flow channel connected to afirst gas source of a first gas, formed inside a ceiling or a sidewallof the treatment container, and communicating with the treatment spacethrough a plurality of first gas discharge holes; a second flow channelconnected to a second gas source of a second gas, formed inside theceiling or the sidewall of the treatment container, and communicatingwith the treatment space through a plurality of second gas dischargeholes; a plurality of first diaphragm valves, wherein each of the firstdiaphragm valves is provided between the first flow channel and thefirst gas discharge hole; a plurality of second diaphragm valves,wherein each of the second diaphragm valves is provided between thesecond flow channel and the second gas discharge hole; a controllerconfigured to bring the plurality of first diaphragm valves and theplurality of second diaphragm valves into operation; a first pressuredetector configured to measure a pressure of a first mixed gas suppliedto the first flow channel; and a second pressure detector configured tomeasure a pressure of a second mixed gas supplied to the second flowchannel, wherein the controller: brings each of the first diaphragmvalves into operation so that a flow rate of the first mixed gas withinthe first flow channel is distributed and controlled for each of thefirst gas discharge holes, brings each of the second diaphragm valvesinto operation so that a flow rate of the second mixed gas within thesecond flow channel is distributed and controlled for each of the secondgas discharge holes, controls degrees of opening of the plurality offirst diaphragm valves on the basis of a relationship between a flowrate, a pressure and a degree of valve opening acquired in advance foreach of the first gas discharge holes, a measurement result of the firstpressure detector, and a target flow rate which is set for each of thefirst gas discharge holes, and controls degrees of opening of theplurality of second diaphragm valves on the basis of a relationshipbetween a flow rate, a pressure and a degree of valve opening acquiredin advance for each of the second gas discharge holes, a measurementresult of the second pressure detector, and a target flow rate which isset for each of the second gas discharge holes.
 2. The gas supply systemaccording to claim 1, further comprising: a first gas box having aplurality of gas sources including the first gas source, and supplyingthe first mixed gas, obtained from the plurality of gas sources, to thefirst flow channel; a first flow rate controller provided between thefirst gas box and the first flow channel; a second gas box having aplurality of gas sources including the second gas source, and supplyingthe second mixed gas, obtained from the plurality of gas sources, to thesecond flow channel; and a second flow rate controller provided betweenthe second gas box and the second flow channel, wherein the first flowchannel is a closed space to which the first mixed gas is supplied, andthe second flow channel is a closed space to which the second mixed gasis supplied.
 3. The gas supply system according to claim 1, wherein eachof the first diaphragm valves and each of the second diaphragm valvesinclude a piezoelectric element that drives a diaphragm, the gas supplysystem further comprises a detector that measures an amount ofdisplacement of the piezoelectric element, and the controller controls adegree of opening of the first diaphragm valve and a degree of openingof the second diaphragm valve using the amount of displacement as aparameter.
 4. The gas supply system according to claim 2, wherein eachof the first diaphragm valves and each of the second diaphragm valvesinclude a piezoelectric element that drives a diaphragm, the gas supplysystem further comprises a detector that measures an amount ofdisplacement of the piezoelectric element, and the controller controls adegree of opening of the first diaphragm valve and a degree of openingof the second diaphragm valve using the amount of displacement as aparameter.
 5. A gas supply method in a gas supply system that supplies agas to a treatment space within a treatment container of a substratetreatment apparatus, wherein the gas supply system includes: a firstflow channel connected to a first gas source of a first gas, and formedinside a ceiling or a sidewall of the treatment container, andcommunicating with the treatment space through a plurality of first gasdischarge holes, a second flow channel connected to a second gas sourceof a second gas, formed inside the ceiling or the sidewall of thetreatment container, and communicating with the treatment space througha plurality of second gas discharge holes, a plurality of firstdiaphragm valves, wherein each of the first diaphragm valves is providedbetween the first flow channel and the first gas discharge hole, and aplurality of second diaphragm valves, wherein each of the seconddiaphragm valves is provided between the second flow channel and thesecond gas discharge hole, a controller configured to bring theplurality of first diaphragm valves and the plurality of seconddiaphragm valves into operation, a first pressure detector configured tomeasure a pressure of a first mixed gas supplied to the first flowchannel, and a second pressure detector configured to measure a pressureof a second mixed gas supplied to the second flow channel, wherein thecontroller: brings each of the first diaphragm valves into operation sothat a flow rate of the first mixed gas within the first flow channel isdistributed and controlled for each of the first gas discharge holes,brings each of the second diaphragm valves into operation so that a flowrate of the second mixed gas within the second flow channel isdistributed and controlled for each of the second gas discharge holes,controls degrees of opening of the plurality of first diaphragm valveson the basis of a relationship between a flow rate, a pressure and adegree of valve opening acquired in advance for each of the first gasdischarge holes, a measurement result of the first pressure detector,and a target flow rate which is set for each of the first gas dischargeholes, and controls degrees of opening of the plurality of seconddiaphragm valves on the basis of a relationship between a flow rate, apressure and a degree of valve opening acquired in advance for each ofthe second gas discharge holes, a measurement result of the secondpressure detector, and a target flow rate which is set for each of thesecond gas discharge holes, the gas supply method comprises: settingeach of the first diaphragm valves to be opened and each of the seconddiaphragm valves to be closed, and supplying the first gas from thefirst gas discharge hole to the treatment space; and setting each of thefirst diaphragm valves to be closed and each of the second diaphragmvalves to be opened, and supplying the second gas from the second gasdischarge hole to the treatment space.
 6. The gas supply systemaccording to claim 1, further comprising a plurality of first flowchannels including the first flow channel and a plurality of second flowchannels including the second flow channel, wherein each of the firstflow channels and the second flow channels is provided inside theceiling and extends from the center of the ceiling toward outer side,and the first flow channels and the second flow channels are arrangedalternately in the radial direction.
 7. The gas supply system accordingto claim 1, wherein the first flow channel is located below the secondflow channel.
 8. The gas supply system according to claim 2, furthercomprising a first valve, a second valve, a third valve, and a fourthvalve, wherein the first flow rate controller is provided between thefirst valve and the second valve, and the second flow rate controller isprovided between the third valve and the fourth valve.